iCloud on Yosemite

Hello, I have two machines which i have kept running Yosemite.

One is a 2012 iMac and the other is an even older MacBook Pro.

I have been unable to access any iCloud services on either machine for several

months despite countless attempts. Have tried Safe Boot and even copying the iCloud folder from another working laptop but nothing works. They simply refuses to accept my password. Strangely though one App

asked me for my password as i had purchased it from the Apple store and it accepted it without problem.

if anyone has come across this before I would be interested to hear.

Or if someone can suggest something to try I would be grateful.

Many Thanks for reading .